A Parisian couple decides to sell an unsanitary basement in their building. A very ordinary, nondescript man, Mr. Fonzic, shows up to buy it. Nothing unusual there, until the man moves into the cellar and makes it his permanent residence. The couple tries desperately to cancel the sale but to no avail. Worse, Mr. Fonzic becomes a threat to their family as he befriends their teenage daughter on whom he seems to exert a perverted influence.

What could be more exciting than getting your Baccalaureate? Lou, Malik, Fiona, Solal, Paul and Théo are finally free! Free to do what they want and ready to do anything to have the best time of their lives. Together, they close the school door behind them, to go on an adventure. It is by train and across Europe that the six friends will discover what it means to become an adult, through encounters and adventures that they are not ready to forget...